ACANTHOPLEURA. 215 



* * This divides into three subsections : 



t A. nobilis Gray. [== Eudoxochiton^] 

 t t A. picea Sow., spinigera Sow., owenii Gray, spinosa Brug., 



brevispinosa Sow., magnified Gray. [=Maugeria.~] 

 t t t A. f gigas Gmel. [==Dinoplax] A. f truncata. \=Ton- 

 ieia.~\ 



Neither of these sections is selected by Gray as typical ; but in his 

 " List of the Genera of Recent Mollusca, their synonyma and types " 

 P. Z. S. 1847, he gives on p. 168, no. 413, " Acanthopleura Guild. 

 1835; Gray, 1847. Canthapleura Swains., 1840. Ch. spinosa" 

 It appears then that not only Swainson, but Gray himself selects G. 

 spinosus as the type species. 



1853. SHUTTLEWORTH, in a most scholarly essay, divided Gray's 

 Acanthopleura of 1847 into three sections : Chcdopleura [equivalent 

 to Gray's sect. * and part of f f t an( ^ including C. rugosus (Gray) 

 Sowb., peruvianus Lm., gigas Chem.] ; Eudoxochiton [for C. nobilis 

 Gray] ; and Acanthopleura, restricted, [equal to Gray's Acantho- 

 pleura sect, f t pl us Corephium, with some other miscellaneous 

 species]. 



In 1856, GRAY again made a cruel onslaught upon the genus ; 

 and here he restricts Acanthopleura to the sect. * of his 1847 

 arrangement, ignoring the fact that Shuttleworth had meantime 

 given a new name, Chcetopleura, to that .section, and apparently 

 forgetting that he had himself said in a former paper that C. spinosus 

 was the type of Acanthopleura ! In the same paper, he proposes a 

 new genus, Maugeria, for the following species, which he arranges in 

 two sections: f, M. nobilis \_= Eudoxochiton Shuttl. 1853]. f t> 

 M. picea Sow., spinigera Sow., owenii, spinosa Sow., brevispinosa 

 Sow., magnifica Sow., C. 111., f. 52. He also retains his genus Core- 

 phium for C. echinatum Sow., 111., f. 47. 



1858. Messrs Adams, in their Genera, reunite Acanthopleura and 

 Corephium, with a choice assortment of other forms, under the 

 genus " Chiton Linnceus" As the status of this generic name has 

 been fully discussed by me on p. 150, comment here would be super- 

 fluous. 



1873-1882. Carpenter, in his MS. arrangement of Chitons (an 

 abstract of which was published by Dall, Proc. U. S. Nat. Mus. 1881, 

 p. 284, 287), proposes to retain the name Acanthopleura for the 

 group of Ch. piceus; Corephium for C. echinatus; and Francisia 

 Cpr., nov., for Ch. spinosus. This arrangement is not acceptable 



